We point out the possibility of probing the nuclear vibration by using the high-order harmonic generation (HHG) with ultrashort laser pulses. By analyzing the HHG spectra obtained from the numerical solution of the time-dependent Schrödinger equation, we find that the intensity of the emitted harmonics is strongly determined not only by the molecular configuration but also by the initial velocity of nuclei. The calculations show that the intensity of HHG is enhanced nearly the time when the internuclear separation takes the equilibrium value and the nuclei are moving closer together. In contrast, with the same initial internuclear separation but with the opposite direction of nuclear velocity, the intensity of emitted light is reduced noticeably. We use that evidence as a tool to probe the nuclear vibration.

• Received 3 April 2013

DOI:https://doi.org/10.1103/PhysRevA.88.023824